Jaw meshing device



1954 c. s. METSGER ETAL 2,665,674

JAW MESHING DEVICE Filed Nov. 24, 1950 2 Sheets-Sheet 1 FIG.1

SAMUEL GILBERT CHARLES S. METSGER Jan. 12, 1954' c. s. METSGER ETAL 2,665,674

JAW MESHING DEVICE Filed Nov. 24, 1950 2 Sheets-Sheet 2 FIG. 2

INVENTORS SAMUEL GILBERT CHARL 5 S METSGEP W Patented Jan. 12, 1954 JAW MESHING DEVICE Charles S. Metsger, Saddle River Township, Bergen County, and Samuel Gilbert, Cedar Grove, N. J assignors to Bendix Aviation Corporation, Teterboro, N. J a corporation of Delaware Application November 24, 1950, Serial No. 197,456

3 Claims. 1

The present invention relates to engine starters and more particularly to improvements in jaw meshing mechanism.

With the development of internal combustion engines such as gas turbines or jets that require a relatively high cranking speed, the conventional starter using a spline nut and a screw shaft for jaw meshing has proven inadequate. It has been found that the turbine type starter is capable of producing the high cranking speeds necessary. One source of power for the turbine is a charge of slow burning powder, known as the solid combustion type. Other means such as steam, mixtures of gasoline and air are also used. In starters of the aforenoted type, the starter jaws attain a high rate of speed in a relatively short time and ii the jaws are not premeshed, will cause an impact shock upon the jaws meshing that is likely to cause serious damage to the starter and engine. Overrunning clutches have been used to connect the starter to the engine but have the disadvantage in that the clutch is subject to constant wear at the high speeds involved and a failure of the clutch will cause the starter to be directly connected to the engine.

In the present invention, the jaw meshing mechanism is incorporated on the engine shaft. The jaws are spring biased into engagement. Upon the engine starting, oil pressure overcomes the bias of the spring and moves the jaws out of engagement.

It is an object of the present invention to provide improved jaw meshing mechanism for engaging a starter to an engine.

Another object of the invention is to provide meshing means normally biased into engagement and responsive to oil pressure for disengagement.

Another object of the invention is to provide an improved engine starter mechanism.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing wherein one embodiment of the invention is illustrated by way of example.

In the drawings:

Figure 1 is a sectional view of the jaw meshing mechanism with the jaws in the engaged position.

Figure 2 is a sectional view of the jaw meshing mechanism with the jaws in the disengaged position.

Referring now to the drawings, wherein only that portion of the engine and starter embodying the invention are illustrated, a cylindrical member 5 is mounted in housing 5 for rotation and relative axial movement by sleeve bearing 1. The housing 6 may be a part of the engine housing or of a mounting ring for attachment to the engine. The member 5 has a radially extending flange 8 which coacts with an axially projecting circumferential flange 9 of the housing member 6 to form a piston and cylinder. A rin H) in the flange 8 provide an oil seal between the flanges 8 and 9. The cylinder 5 has internal splines II and is slidably'splined to engine shaft 12. The end of the engine shaft l2 has a counterbore portion l3 adapted to receive a spring l4. The other end of the spring 14 bears against splined head l5 of a bolt Hi. The bolt I6 is held in the cylinder l5 by a lock ring H.

An engine jaw l8 having a shank portion l9 extending into the cylinder l5 and splined thereto is secured by the bolt [6 and a nut 20. The jaw I8 is adapted to mesh with starter jaw 2| of a starter 22. The starter 22 may be of the type having a source of power, reduction gearing and output shaft, only a portion of the starter 22 has been illustrated inasmuch as starters of the general type are well known to the art. The starter 22 is attached to the housing 6 by studs 23 and nuts 24.

The housing 6 is provided with a recessed chamber 25. Connecting with the chamber 25 is a passageway 26 adapted to connect to an oil pump or pressurized oil system (not shown). A check valve 21 is provided in the opening of the chamber 25 and permits oil to flow outward from the chamber 25. A circumferential channel 28 permits distribution of the oil around the flange 8.

An oil seal 29 prevents oil from entering into the starter 22 and any oil leaking past the bearing 1 is drained off by means of a drain 30.

In operation, when the engine is not running, the spring l4 biases the jaws l8 and 2| into engagement. (See Figure 1.) The jaw 2| is axially rigid and is mounted in the starter 22 for rotary motion only. Upon the engine starting the oil pressure builds up and is carried by the passage 26 through the chamber 25 and circumferential channel 28 and exerts a pressure against the flange 8 to overcome the bias of the spring 14 to move the cylinder 5 axially along the splines of engine shaft l2. As the jaw 18 is secured to the cylinder 5, it is moved out of engagement with the starter jaw 2|. A shoulder 3| on the shaft I2 serves as a stop to limit the movement of the cylinder 5. As long as the oil pressure is maintained the flange 8 will be held by the pressure in the retracted position (see Figure 2) The flanges 8 and 9 coact to form a piston and cylinder. Leakage past the bearing 1 serves as a lubricant for the bearing 1 and is then drained on through the drain 30 into the engine gear case or sump (not shown). 7

A bleed or restriction 32 is provided in the flange 8 to control'the time delay'before meshing after the. engine is shut down. This prevent meshing and ratcheting of the jaws while the engine is coasting to a stop. Should the teeth of the jaws abut, the spring pressure will insure their meshing at the first movement of the starter. In other words,- the jaws will always mesh by the time the starter jaw travels the distance between adjacent teeth. By providing a greater number of jaw teeth, the shock of engagement will b reduced to a minimum.

Although the oil pressure will tend to build up during the cranking operation, the friction between the teeth of the engine and starter jaws will hold the jawsinto engagement until theenine starts.

Thus by eliminatingthe meshing shock, the life of the starter and engine parts is materially increased. Further, coldweather meshing problems are eliminated as thejaws mesh immediately after the engine is shut down and the oil is hot.

Although only; one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement oi the parts, which will now appear to those skilled in the' art, may bemadewithout departing from thescope of the invention.

What isclaimedis:

1. In engine startingapparatus, the combinamember mounted for axial and rotary movement in said housing concentric with said circumferential flange, a radially extending flange on said cylindrical member, said radially extending flange adapted to coact with said circumferential flange to form a piston and cylinder, an engine shaft, means for slidably. connecting said cylindrical member to said engineshaft for r0- tation with and axial movement relative thereto, an engine jaw secured to said cylindrical member for rotation and axial movement therewith, a starter jaw adapted to be engaged by said engine jaw; spring means for normally biasing said jaws into engagemenh'and means for supplying fluid pressure to said piston and cylinder upon the engine starting to actuate said piston to overcomesaid springbias and move said engine jaw out of. engagement.

2; The combination as set forth in claim 1, wherein said fluid pressure is the oil pressure of the engine.

3. The combination as set forth in claim 1 and including an orifice for bleedingofi" said pressure upon said engine being shut down, said orifice providing a time delay to prevent said jaws-from meshing-while said engine is coasting to a stop.

CHARLES S. METSGER. SAMUEL GILBERT.

References. Cited in the file of this patent UNITED 'S'IATES'PATENTS Number Name Date 1,999,199 McGrath V Apr. 30, 1935 2,370,249 Korte et al. Feb. 27, 1945 2,414,359 Carnagua etal. Jan. 14, 1947 2,504,670 Everest r Apr. 18, 1950 

